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Urinary infection (adult)

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IMPORTANT: please note

The vast majority of urinary infections in adults are treated by primary care physicians (GPs). As a general rule, urologists only become involved if further investigations are required, or if other causes have been identified. Referral may be considered for: 

  • stones;
  • poorly-draining bladders;
  • abnormal kidneys; or
  • when infections become recurrent with no obvious cause.

The information on this page does not apply to infants or children.  For advice on urinary tract infection in a child, please click here

What causes urinary infection?

Most urine infections occur when bacteria enter your bladder through your urethra (waterpipe);

Risk factors include:

  • sexual intercourse
  • passing urine infrequently
  • incomplete bladder emptying
  • stones
  • poorly-draining or mis-shapen kidneys
  • catheters;

Most urine infections are caused by a bacterium called E coli (illustrated right). Other types of bacteria may be responsible, and the type of organism can sometimes give a pointer to the underlying problem (e.g. kidney or bladder stones may be associated with a bacterium called Proteus).

How will I know if I have an urinary infection?

Symptoms can vary from very mild to severe, depending on whether the infection is confined to your bladder (cystitis) or has affected your kidney(s) as well (pyelonephritis):

Symptoms of bladder infection

Symptoms of kidney infection

Smelly urine
Passing urine frequently
Urgency (a pressing need to pass urine)
Pain in your lower abdomen (tummy)
Pain in your urethra (waterpipe)
Bloodstained urine

Shaking (rigors) and chills
Pain in your flank (kidney area)

(± symptoms of bladder infection)

How will my urinary infection be confirmed?

The simplest and most important test is analysis of a sample of your urine; this can normally be done at your GP surgery using a special “dipstick” technique. The stick test also looks for other abnormalities in your urine (e.g. protein, sugar, bilirubin).

A more thorough microbiological test, called “microscopy, culture and sensitivity (MC&S)”, is sometimes performed; this requires a mid-stream sample of your urine to be collected into a sterile container, usually at your GP surgery.

Test Advantages Disadvantages

Quick & easy to perform;
Can be done in your GP surgery;
Semi-automated when read by machine; and
Reasonably accurate in detecting infection.

Checks for diabetes, acidity & specific gravity;
Does not confirm the type of bacteria; and
Cannot determine antibiotic sensitivity.


Confirms the type of bacteria present;
Identifies the best antibiotic for treatment;
Identifies antibiotic-resistant bacteria; and
Helps to distinguish different infections.

Can take 48 hours for the result;
Requires transport to the laboratory; and
Requires careful storage if awaiting transport.

How will my urinary infection be treated?

Simple treatment for helping the symptoms include:

  • increasing the amount of fluid you drink
  • taking regular painkillers (e,g, paracetamol) - this also helps reduce any fever
  • taking agents which alkalinise your urine (e.g. bicarbonate of soda or preparations which you can buy from any chemist) - these neutralise the acidity of your urine and improve the burning when you pass urine

Antibiotics are the most effective treatment for urinary infection. The type and dose will depend on various factors, including:

  • your previous history;
  • other medications (drugs) you may be taking;
  • the likely type of bacteria;
  • the result of urine microscopy, culture & sensitivity;
  • previous bacterial sensitivities;
  • the severity of the infection; and
  • how unwell you are.

Bladder infection (cystitis) usually responds rapidly to a short course of antibiotics, but kidney infection (pyelonephritis) generally requires a longer course of treatment. In the UK, antibiotics may only be prescribed by a medically-qualified doctor, or by a nurse with special training.

In severe infections, where you are unwell with severe dehydration, sickness or inability to keep down any fluids you take by mouth, hospital treatment with antibiotics by injection may be necessary.

Will I need further tests?

A single episode of cystitis in a woman that settles quickly on treatment, does not usually need any further investigation.

Recurrent cystitis, pyelonephritis and all urinary infections in men or children should be investigated. Ultrasound scanning is the main method of investigation, looking particularly at bladder emptying.

How can I prevent infections in the future?

There are some self-help measures you can do to help reduce your chance o getting an urinary inection in the uture:

  • wiping from front to back when you go to the toilet;
  • not holding your urine in too long - pass urine when you need to go;
  • passing urine after sex to flush out any bacteria; and
  • drinking enough fluids so you don't get dehydrated.

If these don't help, you may also want to try:

  • D-mannose - this is an alternative therapy (and a kind of sugar) that you can buy over the counter at health food stores or via the internet. Small studies have shown that taking two grams each day can help prevent urine infection to a similar degree as low-dose antibiotics, but more evidence is needed; or
  • cranberry products - although there is little evidence that they are helpful

If these things don't help or are not suitable for you, you may want to think about taking an antibiotic.

Is there anything else I can do?

  • Antibiotic prophylaxis

When lifestyle alterations and increasing your fluid intake on their own do not work, taking a half or quarter dose of an antibiotic, usually last thing at night, does help prevent further infections. This is best started after a full treatment course for a proven infecton, and may help prevent recurrence of the infection. Your GP will be able to advise you about this.

  • Low-dose vaginal oestrogens

Weekly use of an oestrogen cream or tablet, placed into the vagina, can help reduce the number of infections suffered by some women after the menopause. Oestrogens are often given more frequently for the first four to six weeks of treatment.

Are there any newer approaches available?

Despite all the measures described above, some patients with normal investigations continue to get infections, and this can be very debilitating. There are, however, some novel treatments being trialled in urology departments for intractable cystitis. These include:

  • vaccine treatments;
  • urinary antiseptics taken by mouth; and
  • chemical treatments put directly into your bladder through a small catheter.

If your symptoms cannot be controlled by any of the measures outlined above, you should talk to your GP about getting a hospital referral to see a urologist.

For further information about managing recurrent infections, download a self-help guide for women with recurrent recurrent cystitis.

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